In the first season, the Others sent one of their own, Ethan Rom (whose name was even an anagram for the "Other Man"), to spy on the survivors from the front section of Flight 815. Infiltrating the group as a survivor, Ethan was able to fit in until Hurley made a census - showing that Ethan was never on the flight manifest. Upon being discovered as an 'Other,' Ethan abducted Claire and Charlie, for reasons still unknown. The fallout of this situation had an angry Charlie (who can blame him, he was left for dead) shooting Ethan before the rest of the survivors could question him.

While Ethan Rom was not a "good guy," his death was still very significant to the show. His death wasn't so much significant because of the fact that it was Charlie who shot him, but more so because he was the only person on the show up to that point that could have given any information about what is happening on the island. In effect, by killing off Ethan the writers were given plenty of time to string us, the viewing public, along as to who the Others are and what their true intentions may be&#Array; making Ethan's death the most frustrating death so far on Lost.

Yes, Ana Lucia & Libby are technically two Lost deaths but considering they were killed within seconds of each other we decided to bundle them up into one morbid package.

Introduced at the start of season two, both characters had an immediate impact on the series as part of the new group of "tailies." They even had their own flashback episodes and love interests. Suddenly, that all came to an unexpected end in "Two for the Road." Michael shoots both Ana-Lucia and Libby in order to free Ben and eventually be reunited with his son Walt.

Why kill both characters? Some believe that it may have something to do with the two actresses' DUI (Driving Under the Influence) charges that they received weeks earlier. Even Adewale Akinnuoye-Agbaje, who portrayed Mr. Eko, left the series soon after he was arrested for driving without a license. Of course, the show's producers have dismissed this theory. Now that Ana-Lucia, Libby and Mr. Eko have departed&#Array; we can only fear for poor Bernard.

Some of the many fans of Mr. Eko were no doubt watching his final episode, "The Cost of Living" with a sense of dread. After all, the commercials had already announced that someone was dying that week, and Mr. Eko was the subject of the flashbacks on "The Cost of Living"; going by the history of Shannon and Ana-Lucia, if there's a major death, there's a good chance that person gets a flashback episode as a swan song.

But before that week, it was hard to imagine Mr. Eko could be going so soon. Introduced in season two as one of "the tailies" -- the group of survivors who'd been in the tail end of the plane when it crashed -- Eko quickly became a standout on the series and evolved into a fan favorite, with his combination of toughness and calm demeanor. While Ana-Lucia and Libby's deaths were genuinely shocking, Eko was clearly the best and most interesting of the tailies, and it was gratifying to see him evolve into what seemed to be a major character, who would continue on well past his ill-fated fellow tailies.

However, as we all know now, that wasn't the case, as Eko instead met his maker just a few episodes after Ana-Lucia and Libby. Eko had seen the mysterious smoke monster before, but his second encounter would prove much more dire, as the smoke monster showed much more direct aggression and action than we'd ever seen from it, grabbing Eko and physically smashed him against the trees repeatedly, before slamming him to the ground in a final death blow.

Locke said Eko's final words were a warning that the rest of the survivors were next, which doesn't bode well for any of them. One thing is for sure; Eko's death proved that the unexplained smoke monster was something that those on the island very much needed to fear and be on guard against. We're just sorry it took the demise of such a cool and interesting character in order to get that message across.